Vickers range clock: differenze tra le versioni

Versione delle 17:52, 27 feb 2013

Versione delle 17:53, 27 feb 2013

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Once some shots had been fired, spotters would report the fall of shell (which could be observed because of the large waterspouts where the shells hit the sea) and the range would be corrected up or down depending whether the shells were short or over the enemy. Initial estimates of range were obtained using optical rangefinders.

The dial was fitted with three separate scales reading {{convert|2000|-|6000|yd|m|abbr=on}}, {{convert|6000|-|10000|yd|m|abbr=on}} and {{convert|10000|-|14000|yd|m|abbr=on}} in 100-yard steps, with marked subdivisions every {{convert|25|yd|m|abbr=on}}. The handle for adjusting the dial was added from 1908; previously, the initial position of the dial plate had to be set by rotating it directly. Initial models had the rate setting dial calibrated in both knots and 'seconds per 50 yards'. This was altered in 1909 to yards per minute, which standardised measurement was used on other equipment designed to work with the clock.<ref>Brooks p.53-54</ref>

An important aspect of the Vickers range clock, as well as other designs using a wheel-on-disc drive for the variable speed motor, such as the electrical clock used in the [[Frederic Charles Dreyer#Dreyer Fire Control Table|Dreyer Fire Control Table]], was that it could only generate ranges according to a constant range rate. In most firing scenarios, the range rate would change continuously. In such cases, the operators of the clock would periodically alter the range rate in discrete increments as conditions suggested.